1. Field of the Invention
The present invention relates to an image display apparatus used for displaying characters and images, such as a display of a television receiver or a computer, and a message board, and a manufacturing method thereof.
2. Related Background Art
As an image display apparatus which has been generally spread widely, a color cathode ray tube (CRT) can be cited. Because the driving principle of the color CRT is that electron beams from the cathode thereof are deflected to make phosphors on the screen thereof emit light, the color CRT needs a depth according to the screen size thereof. Because the depth becomes long as the screen becomes large, the color CRT has problems of the expansion of the setting space thereof and of the increase of the weight thereof. Consequently, a thin-shaped flat type image display apparatus capable of being made to be light is strongly desired.
As the flat type image display apparatus, there are ones using plasma discharge, using a liquid crystal device, and using a vacuum fluorescent display. As the flat type image display apparatus attracting attention owing to its high picture quality and its low power consumption, a displaying apparatus using electron-emitting devices can be cited. The displaying apparatus using the electron-emitting devices is a displaying apparatus using a phenomenon of causing luminescence by the collision of electrons emitted in the inside of a vacuum chamber to a phosphor, to which a high voltage is applied. Accordingly, it is necessary to perform hermetic sealing of a voltage supplying path in the vacuum chamber. Japanese Patent Application Laid-Open No. 2003-92075 discloses concrete means of the hermetic sealing.
The configuration of the voltage supplying path to the phosphor disclosed in the Japanese Patent Application Laid-Open No. 2003-92075 is schematically shown in FIG. 11. In FIG. 11, reference numeral 100 denotes a leading wire, reference numeral 101 denotes a lead-in wire, reference numeral 102 denotes an insulating member, reference numeral 103 denotes a hermetic lead-in terminal, reference numeral 104 denotes frit glass, reference numeral 105 denotes a stand-alone wire, reference numeral 106 denotes a pressure structure, reference numeral 110 denotes a face plate, reference numeral 111 denotes a rear plate, reference numeral 112 denotes an electron source area, reference numeral 114 denotes an outer frame, and reference numeral 120 denotes an image-forming member.
In the configuration of FIG. 11, a hermetic container is formed by sealing the face plate 110, the rear plate 111 and the outer frame 114 with the frit glass 104. A voltage is applied to the leading wire 100 lead from the image-forming member 120 provided with the phosphor through the lead-in wire 101 lead-in from the outside. The lead-in wire 101 is configured as the hermetic lead-in terminal 103, in which the insulating member 102 is disposed around the lead-in wire 101. The hermetic lead-in terminal 103 adheres to a through-hole formed in the rear plate 111 with the frit glass 104, and thereby the hermetic sealing of the hermetic lead-in terminal 103 is performed.
However, because the calcination temperature of the frit glass is 350° C. or more, which is very high, in the above-mentioned method, in which the hermetic lead-in terminal 103 adheres with the frit glass, the process cost of the method is high, and the high process cost is the primary factor of raising the cost of an article. Moreover, because the frit glass contains lead, the frit glass has a problem on environmental health.